Rotating folder for printing presses

ABSTRACT

A rotating folder for printing presses in which a movable folding blade operating against a fixed folding blade stop is associated with each folding knife, comprising a folding blade cylinder and a driven shaft between which is arranged a torsion element and a clutch equipped with jaws which are trapezoidal over a part of their length, and a fixed stop is provided to limit the width of opening of the clutch which amounts at most to only two-thirds of the length of the jaws.

States Hertrich A Jan. 22, 1974 ROTATING FOLDER FOR PRINTING 3,517,920 6/1970 Snyder 270/77 PRESSES 3,602,345 I 8/1971 Rattenberg et a1. l92/l08 x 75 in t 11.1 '11 11 i or am ertnc Gohrenz Germany Primary ExaminerRobe rt W. Michell [73] Ass1gnee: VIEB Polygraph Leipzig, Kombinat Assistant Examiner-Milton C. Y. Mui

fiuer polygraphische Maschinen u. Attorney, Agent, or Firm-Ernest G. Montague Ausruestungen, Leipzig, Germany [22] Filed: Feb. 2,.1971 [57] ABSTRACT PP N03 0 A rotating folder for printing presses in which a movable folding blade operating against a fixed folding blade stop is associated with each folding knife, com- 52 U.S. 1. 27 Km 8 B65! prising a folding blade cylmder and a drlven shaft be- [58 w 39 41 47 tween which is arranged a torsion element and a 270/50 72 73 74 76 192/67 R 108 clutch equipped with jaws which are trapezoidal over a part of their length, and a fixed stop is provided to 1 11 11 1:11:11,111: UNITED STATES PATENTS Fig Sa mos e e g 1,997,126 4/1935 Spillane 270/13 X 2,848,905 8/1958 Evans; 192/67 R X 5 Claims, 6 Drawing Figures ELECTRO- MAGNET mgy FIG. 2.

PATENTED 3,787,043

" SHEEI1UF 2 FIG, T. 70,

ELECTRO- MAGNET PNEUMATIC WORK CYLINDER .MEANS CYLINDER g W5 7b 7 I KLAUS HERTERICH FIG. 6.

ATTORNEY.

PATENTEDJANZQIW 3.787. 043

INVENTOR K AUS HERTERICH ATTRNEY.

ROTATING FOLDER FOR PRINTING PRESSES same way as in the forward operation. The disadvantage of this device is that as a result of wear and of preexisting bearing play in the two folding blades, relatively large sources of error result. inaccurately folded products are then the result. I

For this reason there is an increasing shift towards apparatus in which one moving folding blade cooperated with one rigid folding blade stop. In this case difficulties result, however, if for any reason, for instance, as a result of stoppers, a rearward movement of the folding cylinder is necessary. In such a case, as soon as the folding knife cylinder during the reverse movement remains as a result of normalgear clearance, or the like, even merely slightly behind with respect to the folding blade cylinder, there is the danger that the folding knife will strike against the fixed folding blade stop and be damaged. This has been remedied by omitting the rearward travel entirely and in the manner that when rearward travel becomes indispensable, the manufacturer recommends removing the folding knives.

Now, however, in the case of rotating folders which are directly connected with web-fed rotary presses, it is necessary to effectrearward travel for various and particularly purely technological resons, namely, upon the introduction of the printing plates or rubber blankets, for instance, of a web-fed rotary offset press. For this operation the folding machine could, it is true, be disconnected. Since in particular the re-connecting of the folding machine is very time consuming, it is not desirable to do so. Some known devices nevertheless require the disconnecting of the folding machine and offer the user, in order to save time, an automatic, relatively expensive coupling device. Another case in which the rearward movement of the cylinders of the folding machine is necessary, results for reasons of protection of the workers. If, for instance, due to carelessnessan article of clothing or the like should be caught,

immediately-rearward travel is necessary and in such case, if immediate assistance'is necessary, it would be impossible, then first of all, to remove the folding knives.

From German Pat. No. 257,644 there are known devices in connection with which the folding knife is guided by fingers arranged on the folding blade between the folding blade and the folding blade stop even upon the rearward rotation of the machine. At high speeds, however, there is an intolerable amount of noise and extensive wear due to the sliding of the parts on each other so that use thereof does not enter into consideration in the case of high-speed machines.

In accordance with German Pat. No. 633,756, it is already known to make the folding knives movable, i.e., retractable to within the periphery of the folding knife cylinder. in this case, however, the same problem arises as in all other controlled folding knife movements. The control is effected by cams which move uniformly corresponding to the speed of the folding knife cylinder. As a result, the folding knives carry out the same movements upon rearward, as upon normal operation. In this case also there is the result that upon rearward travel, the folding knife can strike against the folding blade stop.

It is an object of the present invention to avoid the disadvantages of the prior art, and it is an object of the present invention to provide a folding apparatus in which a separating of the folding apparatus from the printing press during the rearward travel is unnecessary but in which, however, on the other hand, assurance can be definitely had that the folding knife will not strike against the folding blade stop.

It is another object of the present invention to provide a folding apparatus in which it is possible for the operators to start the rearward movement without any great mental effort.

In accordance with the present invention, this result is achieved in the manner that between the folding blade cylinder and its driven shaft there is arranged a torsion element, and a clutch over a part of its length 7 with'trapezoidal jaws. In order to limit the width of opening of the clutch, which amounts at most to twothirds of the length of the jaws, a stop is provided.

In accordance with another feature of the invention, the clutch which is controlled in known manner as a function of the control current for the forward or backward movement of the printing press or of the rotating folder can be actuated in opposition to the force of a compression spring, by an electro-magnet. It is, however, also possible, in order to control the clutch, to use a pneumatic or hydraulic operating work cylinder which can be actuated as a function of the control current.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:

FIG. 1 is a front view of the folding blade cylinder, partially in section;

FIG. 2 is a top view of the jaw of the clutch corresponding to the arrow A in FIG. 1 in a position of the clutch during the rearwardmovement of the cylinder;

FIG. 3 is a schematic illustration of the rotating folder in a position of the folding elements during the forward or operating movement; and

FIG. 4 is a schematic illustration as in FIG. 3 but in a position of the folding elements which they assume during the rearward movement;

, FIG. 5 is a schematic illustration similar to FIG. 1 but broken away in part, illustrating a pneumatic work cylinder means for actuating the clutch; and

FIG. 6 is similar to FIG. 5, but illustrating a hydraulic work cylinder means for actuating the clutch.

Referring now to the drawings, and more particularly to FIG. 1, a rotating folder for printing presses comprises a folding blade cylinder 1 arranged for idling and merely secured against axial displacement on the shaft 4 which is supported in the machine walls 2 and 3. Into recesses 5 which are provided in one of the end walls of the folding blade cylinder, jaws 6 of a jaw clutch 7 extend; by which the rotation of the shaft 4 is transmitted to the folding blade cylinder 1. For this purpose the shaft 4 can either be formed on this side in known manner as a spine shaft or else a key 8 can be provided. The jaws 6 are formed trapezoidally over about one-third of their length, as are the recesses which can constitute the fixed clutch side of the jaw clutch 7.

The folding blade cylinder 1 is connected with the shaft 4 also by a torsion element 9, for instance a helical shaft 4 also by a torsion element 9, for instance a helical spring resting on the shaft 4 and the bore hole of the folding blade cylinder 1, and it has on its periphery one or more controlled folding blades and a fixing folding blade stop 11 (FIG. 3).

During the forward movement of the rotating folder (FIG. 3), the jaws 6 are completely within the recesses 5, i.e., the clutch 7 is closed. In this condition therefore the folding blade cylinder 1 is connected firmly and without clearance to the shaft 4 by the clutch 7.

As soon as a rearward movement is to be introduced, the clutch 7 is opened via an actuating means which may comprise an electromagnet means 7a, hydraulic work cylinder means 7b (FIG. 6) or pneumatic work cylinder means 7c (FIG. 5) or the like as a function of the control current for the rearward movement of the rotating folder or printing press, i.e., it is pulled back against a stop 12 which is connected with the machine wall 3 or rests against it.

The size of the opening is in this connection at most two-thirds of the length of the jaws 6; in other words, the folding blade cylinder 1 continues to be connected with the shaft 4 even when the clutch 7 has been opened. By the torsion element 9 and the inertia of the folding flap cylinder 1 which acts during the starting of the rearward motion, the oblique surfaces of the trapezoidal parts of the jaws 6 and of the recesses 5 come together (FIG. 2) so that the folding blade cylinder 1 remains behind the folding knife cylinder 13 by the amount of angular rotation of the clearance thus produced in the clutch 7, although spur gears 14 and 15 of the folding knife cylinder 13 and the folding blade cylinder I still mesh as normal without play.

In particular, upon the decelerating of the rearward movement of the cylinders,'the torsion element 9 continues to insure that during this period of time also the two oblique surfaces rest against each other. A reversing switch 16 which is actuated by the clutch 7 insures, during the return movement of the cylinder that the control current for the forward movement is blocked in known manner, and vice versa.

The manner of operation of the invention will again be briefly discussed with reference to FIGS. 3 and 4 of the drawing of the illustrative embodiment. During the forward movement of the cylinders, as is shown in FIG.

3, the folding knife 17, with the folding blade 10 opened, comes under the periphery of the folding blade cylinder 1; the controlled folding blade 10 is, as is known, closed only after the entrance of the folding knife 17. Upon the rearward travel of the clyinders, as shown in FIG. 4, the folding knife 17 and the fixed folding blade stop 11, however, move towards each other so that upon the entrance of the-folding knife 17 into the periphery of the folding blade cylinder 1, the folding knife 17 may be damaged. Due to the fact, however, that the folding blade cylinder 1 in accordance with the present invention, due to the partially opened clutch 7, remains back by an amountequal to the amount of the clearance produced, the fixed folding blade stop 11 also remains back so that the danger of the folding knife 17 striking against the fixed folding blade stop 11 is definitely excluded.

While I have disclosed one embodiment of the present invention, it is to be understood that these embodiments are given by example onlyand not in a limiting sense.

I claim:

1. A rotating folder for printing presses in which a movable folding blade operating against a fixed folding blade stop is associated with each folding knife, comprising a folding blade cylinder adapted to cooperate with a tangential folding knife cylinder having a folding knife mounted on its periphery,

a fixed folding blade stop on the periphery of said blade cylinder,

a movable folding blade on the periphery of said blade cylinder, operating against said fixed folding blade stop,

a driven shaft on which said folding blade cylinder is idlingly disposed thereto,

a torsion element operatively connected to and between said folding blade cylinder and said driven shaft,

a clutch equipped with jaws operatively disposed between said driven shaft and said folding blade cylinder said folding blade cylinder having on one end thereof recess means to receive said jaws, said recess means having an initial trapezoidal portion, said jaws having an initial trapezoidal portion extending a part of their length,

a fixed stop disposed relative to said clutch such that when said clutch operatively abuts said stop the retraction of the jaws of said clutch from said recess is limited to at most to only two-thirds of the length of said jaws, and

means for operating said clutch for causing said trapezodial part thereof to be selectively rotracted to come into registry with said trapezodial portion of said recess, and when in said registry causing an angular displacement of said folding blade cylinder by the extent of said trapezodial part relative to its position on said driven shaft when out of registry, whereby said folding blade stop is displaced relative to said folding knife on said folding knife cylinder.

2. The folder, as set forth in claim 1, wherein said jaws are parallel to and axially displaceable relative to the axis of said cylinder, 5

said clutch is mounted on said driven shaft for joint rotation therewith,

said cylinder is formed with said recess into which said jaws extend, said recess and jaws cooperatively formed such that rotation of said jaws cause rotation of said cylinder,

said jaws are inserted completelyin said recess in the closed position of said clutch and are partially inserted in said recess in the open position of said clutch, and

the oblique surfaces of said trapezodial part of said jaws abut the oblique surfaces of the trapezodial portion of said recess in the open position of said clutch and causes a predetermined relative angular displacement of said cylinder with respect to said driven shaft, said clutch still operatively connecting said cylinder for joint rotation to and with said driven shaft.

3. The folder, as set forth in claim 1, wherein forward and rearward movement of the printing press or rotating folder.

5. The folder, as set forth in claim 1, wherein said actuating means comprises a hydraulic work cylinder means for controlling said clutch and operable as a function of the control current for the forward and rearward movement of the printing press or rotating folder. 

1. A rotating folder for printing presses in which a movable folding blade operating against a fixed folding blade stop is associated with each folding knife, comprising a folding blade cylinder adapted to cooperate with a tangential folding knife cylinder having a folding knife mounted on its periphery, A fixed folding blade stop on the periphery of said blade cylinder, a movable folding blade on the periphery of said blade cylinder, operating against said fixed folding blade stop, a driven shaft on which said folding blade cylinder is idlingly disposed thereto, a torsion element operatively connected to and between said folding blade cylinder and said driven shaft, a clutch equipped with jaws operatively disposed between said driven shaft and said folding blade cylinder said folding blade cylinder having on one end thereof recess means to receive said jaws, said recess means having an initial trapezoidal portion, said jaws having an initial trapezoidal portion extending a part of their length, a fixed stop disposed relative to said clutch such that when said clutch operatively abuts said stop the retraction of the jaws of said clutch from said recess is limited to at most to only two-thirds of the length of said jaws, and means for operating said clutch for causing said trapezodial part thereof to be selectively rotracted to come into registry with said trapezodial portion of said recess, and when in said registry causing an angular displacement of said folding blade cylinder by the extent of said trapezodial part relative to its position on said driven shaft when out of registry, whereby said folding blade stop is displaced relative to said folding knife on said folding knife cylinder.
 2. The folder, as set forth in claim 1, wherein said jaws are parallel to and axially displaceable relative to the axis of said cylinder, said clutch is mounted on said driven shaft for joint rotation therewith, said cylinder is formed with said recess into which said jaws extend, said recess and jaws cooperatively formed such that rotation of said jaws cause rotation of said cylinder, said jaws are inserted completely in said recess in the closed position of said clutch and are partially inserted in said recess in the open position of said clutch, and the oblique surfaces of said trapezodial part of said jaws abut the oblique surfaces of the trapezodial portion of said recess in the open position of said clutch and causes a predetermined relative angular displacement of said cylinder with respect to said driven shaft, said clutch still operatively connecting said cylinder for joint rotation to and with said driven shaft.
 3. The folder, as set forth in claim 1, wherein said means for actuating said clutch comprises an electro magnet means, and said clutch is adapted to be controlled as a function of the control current for forward and rearward movement of said printing press or of said rotating folder.
 4. The folder, as set forth in claim 1, wherein said actuating means comprises a pneumatic work cylinder means for controlling said clutch and operable as a function of the control current for the forward and rearward movement of the printing press or rotating folder.
 5. The folder, as set forth in claim 1, wherein said actuating means comprises a hydraulic work cylinder means for controlling said clutch and operable as a function of the control current for the forward and rearward movement of the printing press or rotating folder. 